Clickless listening and ringing key



Jan. 1, 1963 A. A. ADAMSKI 3,071,657

CLICKLESS LISTENING AND RINGING KEY Filed April 29, 1960 2 Sheets-Sheet 1 3 1 mm mm w 3 Q Hula, 7W 24 um lllll 27 um HI mu 6 INVENTOR.

ADOLPH A. ADAMS/U A TTORNE Y Jan. 1, 1963 A. A. ADAMSKI 3,071,657

CLICKLESS LISTENING AND RINGING KEY Filed April 29, 1960 2 SheetsSheet 2 ilnitcd States Patent @ffice Patented Jan. 1, 1963 3,071,657 CLICKLESS LISTENING AND RINGING KEY Adolph A. Adamski, Rochester, N.Y., assignor to General Dynamics Corporation, Rochester, N.Y., a corporation of Delaware Filed Apr. 29, 1960, Ser. No. 25,579 2 Claims. (Cl. 290-1) The present invention relates to a three position switching key and more particularly to a telephone listening and ringing key.

Key structures of the type disclosed in the present invention are characterized by a manually operable lever which may be rotated from a neutral non-operated position clockwise or counter clockwise through a prescribed angle about a fixed axis of rotation to effect the closure or opening of spring contact sets. The switch lever may be retained in an operated position, i.e., an operated position by a locking spring which may be included in the spring contact sets.

In general, the locking spring is a cantilever type being fixed at one end and having a bent portion turned outward in the path prescribed by a roller mounted on the lever in a manner well known to those skilled in the art.

. Equally well known to those skilled in the art is the inherent whipping action of the locking spring when the switch lever is released from an operated position. The locking spring suddenly and forcibly accelerates the switch lever from the first operated position past the neutral non-operating position causing a momentary overthrow of the switch lever into the opposite operating position before settling back to the neutral position.

Three position switching keys having locking springs just discussed have been found to work satisfactorily for the purpose for which they were intended. However, when three position switching keys are equipped with spring contact sets in both operated positions, for example, telephone listening and ringing keys, the cantilever locking spring may cause an objectionable condition. This objectionable condition is experienced when the lever is released from the locked position. The switch lever may rotate about the axis to the other operating position momentarily to effect the closure or opening of the spring contact sets.

In telephone circuits in which listening and ringing keys of this type are used, the objectionable characteristic is characterized by a click, which may be audible in a subscribers telephone set connected to the current carrying lines in which the key is actuated.

Telephone listening and ringing keys which eliminate the click may be called clickless listening and ringing keys.

Accordingly, it is the general object of the present invention to provide a new and improved switching key.

it is another object of the invention to provide a novel means for automatically locking the switch lever in three stable positions, namely, a neutral non-operated position and two operated positions.

It is still another object of the invention to provide a novel I. sans for preventing the overthrow of the switch lever past the neutral non-operated position when released from' an operated position.

It is yet another object of the present invention to provide a single mechanical means for automatically locking the lever in the three positions of the switching key and to eliminate the overthrow of the switch lever.

Another object of the invention is to provide a switching key that may be easily converted from a locking type to a non-locking key.

It is the particular object of this invention to provide an improved clickless listening and ringing key.

Briefly, the switching key in accordance with the present invention comprises a U-shaped frame, a switch lever rotatably mounted in the frame about a given fixed axis on the frame, spring contact sets and resilient detent means for retaining the switch lever in predetermined positions.

The predetermined positions may be a central neutral non-operated position and clockwise and counter-clockwise switch operated positions. The spring contact sets are positioned on the frame in the operated positions to be actuated by the switch lever. For this purpose the switch lever includes first and second contact spring actuating rollers spaced apart at a given radial distance from the given axis.

In accordance with the invention the resilient detent means for locking the switch lever in predetermined positions comprises a resilient member including a detent positioned in the space between the first and second rollers when the switch lever is in the neutral non-operated position mounted on the frame and indents on the distal end of the roller axially aligned thereon. The detent is positioned to come into positive engagement with the indent of the first roller in response to the lever being rotated clockwise through a first given angle from its neutral position and to come into positive engagement with the indent of the second roller when provided in response to the lever being rotated counter-clockwise through a second given angle from the neutral position in a three position locking type key. The resilient detent means prevents the over travel of the switch lever past the neutral non-operated position by automatically snapping into the space between the first and second roller when the switch lever enters the neutral non-operated position.

Further objects and advantages of the invention will become apparent as the following description proceeds and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of the invention, reference may be had to the accompanying drawing of a single preferred embodiment in which:

FIG. 1 is a side view in elevation of the switching key in a normal non-operated position.

PEG. 2 is an end view of the switching key with a portion of the contact springs removed to expose contact spring actuating rollers mounted on the switch lever;

FIG. 3 is a side view of the switching key in an operated position;

FIG. 4 is a fragmentary end View in section of the key in a normal non-operated position taken through line 4-4 of FIG. 1, showing ball-detents in the space between two rollers;

FIG. 5 is a partial detail in side section taken through line 5-5 of FIG. 4, clearly showing the position of the ball detents relative to the rollers when the switch lever is in the normal non-operated position;

FIG. 6 is a fragmentary end view in section taken along line 66 of PEG. 3 showing the ball-detents seated in the indents of the indent rollers when the cam is in an operated position; and

FIGS. 7, 8 and 9 are views similar to FIG. 5 showing the various combinations of rollers for making a locking and non-locking type switch.

Since listening and ringing key structures to which the present invention is applied are well known in telephone practice, it is not believed necessary to disclose the details of all of the various features and parts of the key structure except those relating to the application of the present invention to the previously described key structures.

The key emboding the features of this invention coinprises a one-piece frame 1 substantially U-shaped having parallel first and second side plates 2 and 3, respectively, a bight portion 4 connecting the parallel side plates 2 and 3 across the top of the key and inwardly turned end plates 5 and 6 extending perpendicularly from each side plate 5 and 6 nesting together to form a box-like structure 7 across the lower portion of the frame 1. The box-like structure 7 serves to mount two sets of spring contacts on each of the diametrically opposite end plates 5.

The spring contact sets are secured to the box-like structure 7 by means of suitable screws 3 which pass through the various components of the contact spring sets and screws into each end plate 5 and 6. This type of construction insures that the contact springs are rigidly and correctly located on a frame with respect to a centrally disposed operating switch lever 10 and at the same tice ties in the side plates 5 and 6.

The switch lever 19 is mounted to rotate within the frame 1 by a shaft structure comprising a frame pin 11 which is fixed in a prepared opening in the side plates 2 and 3 and a bushing 12 to which the lever 14) is fixed. The frame pin 11 and bushing 12 are closely fitted in such a manner that bushing 12 is free to rotate on pin 11 Without any appreciable shake. FIGURES 4 and 5 illustrate the co-action between the pin 11 and bushing 12 when the lever 19 is rotated clockwise or counterclockwise from a neutral position. FIGURE 6 shows one means by which the bushing 12 may be fastened to the lever 10. The means for fastening the bushing 12 to the lever 11; may be a knurl 13 roller on the outside diameter of the bushing and pressed into a prepared hole 14 in the lever 10. It is apparent, therefore, that the lever 10 rotates as a stable body about the pin 11 and that a force applied normal to the lever in its direction of travel will be balanced by the stabilized effect of the bushing 12.

The switch lever 10 includes a handle 15 at its upper portion, insulated lever rollers 17 and lever indent rollers 18 and roller pins 19 rotatably supporting the rollers 17 and 18. The pins 19 may be fastened to the lever in a manner similar to the bushing 12 as shown in FIG- URE 6. The roller pins 19 are mounted at right angles to the lever 10 and positioned at a given angular and radial distance from the frame pin 11. The given angular distance of the pin is fixed relative to the spring contact sets mounted on the frame 1. Lever rollers 17 and indent roller 18 will be explained more in detail in conjunction with the features of the invention; but, for the present, the current application of the insulated rollers is to deflect outward certain spring contacts of the contact spring sets to open or close associated electrical circuits. The handle 15 which is made from insulating materials may be fastened to the lever by a threaded extension 16 of the lever It).

The switch contact sets may comprise an operating spring 29 and a number of circuit controlling springs 21, 22, and 23, separated by insulating strips 34. The circuit controlling springs 21, 22, and 23 are fabricated in a manner well known to those skilled in the art and form no part of this invention. The operating springs 2% are tensionecl against the rollers 17 and 18 to return the switch lever 10 to the neutral position. Thus, since the operating springs 29 serve only in the present case by their resiliency to return the lever 16 to the neutral non-operated position, these operating springs so may be made with a smaller spring constant than locking type springs and in this way decrease the amount of force required to operate the switching key. The operating spring 2% may be a simple rectangular shaped leaf-spring of nickel silver or other suitable material. Excessive wear on the operating spring 29 is reduced by the rolling action of the rollers 17 :and 18 on the operating spring 20.

In accordance with the invention, the above described switching key structure includes resilient detent means for the combined purpose of eliminating the 0ver-throw characteristic of the switching lever 10 and for retaining the switch lever automatically locked in an operated position and in the neutral non-operated position. ie resilient detent means comprises a resilient member 24, balldetents 25, an indent 26 positioned in the distal end of the roller 18 and screws 27 to fasten the reslient member 24 to frame 1. The ball-detents 25 may be hardened steel balls positioned to enter the indents 26 on rollers 18, when rollers 17 are in a first operated position and to occupy the space between rollers 17 and 18 when the lever 10 is in a neutral non-operated position. For this purpose, holes 28 are provided in the side plates 2 and 3 positioned at a point in the path prescribed by the indent 2%. In this arrangement the ball-detents 25 are in constant rolling contact with rollers 17 and 18 normal to the direction of travel of the lever 10. Rolling contact between the ball-detent 25 and the rollers 17 and 18 reduces excessive wear.

The resilient member 24 may be a fiat rectangular leafspring fixed at one end to the side plate 2 and 3 by screws 27. A hole 30 is provided at the free end of the resilient member 24 for the ball-detent 25. A chamfer 31 may be coined on the rim of hole 30 in order to reduce the friction between ball-detent 25 and resilient member 24. While it is not absolutely necessary that the balldetent 25 roll on the rollers 17 and 18, it does offer advantages by reducing friction between the cooperating parts. The combination of the ball-detent 25 and resilient member 24 may be modified into different embodiments of the invention as will be discussed later.

To illustrate the operation of the telephone listening and ringing keys, assume that moving the handle 15 counter-clockwise is the listening position as shown in FIGURE 3; and that moving the handle clockwise from the neutral position, is the ringing position. As it is well known the ringing position is momentarily actuated to call a subscriber by energizing the ringer in a telephone sub-set. It is not necessary to lock the switch lever 10 in the ringing positions since telephone systems may employ automatic ringing circuits. The switch lever may be locked in the listening position so that the operator can work hands free of the switching keys while still listening to a subscriber. Referring in particular to FIG- URE 3, the lever 10 is moved clockwise about the frame pin 11 causing the ball-detents 25 to move normal to the switch lever 10 on the rollers 18, while the indent 26 scribes a circular path about the frame pin 11. The ball-detents 25 enter the indent 26 when the rollers 17 depress operating spring 20 so as to close a circuit between spring 22 and 21. t should be noted that as the ball-detent 25 rolls on the roller 18, the roller 18 also rotates so that various surfaces of the indent 26 are presented to the ball-detent 25 in order to distribute wear on the periphery of the indent 26. To restore the switch to the neutral position, the lever 10 is moved clockwise about pin 11 causing the indent 26 to leave the ball-detent 25. The ball-detent 25 rides on the distal end of the roller 18 while the lever 10 is rotated until it snaps into the space between the rollers 18 and 17 automatically locking the lever 10 in a neutral non-operated position, thus preventing any overtravel of the switch lever 10 and also to give a sense of being in the neutral position.

In the ringing cycle of the switching key the lever 10 is rotated clockwise about the pin 11 causing the indent ball 25 to move normal to the switch lever 19 and roll on roller 17. The switch lever 10 may be rotated until lever stop 32 abuts the frame 1. When the handle 15 is released the operating spring 2 automatically returns the lever 10 to the neutral position where the ball-detents 25 snap into the space between rollers 17 and 18 and again prevents the overtravel of the lever 10 past the neutral position. While there has been disclosed what is at present consid- 5, ered' to be the preferred embodiment of the invention, modifications thereto will readily occur to those skilled in the art; for example, it may be obvious to those skilled in the art that the switching key may be a three way locking key having indent rollers 18 on the roller pins 19 replacing detent rollers 17, as shown in FIG. 8. A non-locking type of key may be provided by employing only rollers 17 on pins 19, as shown in FIG. 9. Regardless of what combination is shown in FIGS. 5, 7, 8 and 9 is used, the listening and ringing key still operates as a clickless key because a detent will snap automatically into the space between the rollers when the switch lever ltl is returned to the neutral position.

The resilient member 24 and ball-detent 25 may be combined into a single member. The resilient member 24 may have a spherical projection in place of the ball-detent 25 to occupy the space between the rollers.

In another embodiment of the switching key, one of the resilient detent means 24 and ball-detent 25 may be removed from one side of the switch frame 1. Rollers 17 and 18 and detent member 24 and ball-detent 25 on one side of the switching key will function in a similar manner heretofore mentioned. This is possible because of the shaft structure previously described comprising the frame pin 11 and bushing 12.

It may also be obvious to those skilled in the art that the rollers 17 and 18 may be replaced by projections on the switch lever 10, and when it is desired that the switch be locked in one position or the other, indent 26 should be provided accordingly on the distal end of the projections. Other modifications thereto will readily occur to those skilled in the art. It is not, therefore, desired that the invention be limited to the specific arrangement shown and described, and it is intended in the appended claims to cover all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. A switch comprising a frame, a member rotatable about a given axis on said frame, said member including first and second roller pins juxtapositioned thereon at a given radial distance from said given axis, the longitudinal axis of said first and second pins being substantially parallel to said given axi-s, first and second rollers each having a distal end and a proximal end substantially perpendicular to the longitudinal axis thereof, end of said first and second rollers having an axial bore on said proximal end thereof for rotatably mounting said first and second rollers on said first and second roller pins, respectively, resiliently secured detent means including a detent positioned in the space between said first and second rollers when said member has a given neutral position, at least one of said first and second rollers having an indented surface on said distal end thereof, said detent being positioned to come into positive engagement with said indented surface on said distal end of said one end roller in response to said member rotating through a first given angle in a first direction from its neutral position, first and second spring contacts, said first spring contacts being positioned on said frame to be actuated by said second roller in response to said member being rotated through said first given angle and said second spring contacts being positioned to be actuated by said first roller in response to said member being rotated through a second given angle.

2. The switch defined in claim 1 wherein each of said first and second rollers have an indented surface on said distal end thereof, said detent being positioned to come into positive engagement with said indented surface on said distal end of said first roller in response to said member rotating through a first given angle in one direction from its neutral position and to come into positive engagement with said indented surface on said distal end of said second roller in response to said member rotating through a second given angle in the other direction from its neutr-al position.

References Cited in the file of this patent UNITED STATES PATENTS 1,062,185 Pierce May 20, 1913 1,951,530 Richter Mar. 20, 1934 2,184,780 Little Dec. 26, 1939 2,351,236 Smiley et al June 13, 1944 2,414,191 Coon Jan. 14, 1947 FOREIGN PATENTS 169,623 Austria Dec. 10, 1951 

1. A SWITCH COMPRISING A FRAME, A MEMBER ROTATABLE ABOUT A GIVEN AXIS ON SAID FRAME, SAID MEMBER INCLUDING FIRST AND SECOND ROLLER PINS JUXTAPOSITIONED THEREON AT A GIVEN RADIAL DISTANCE FROM SAID GIVEN AXIS, THE LONGITUDINAL AXIS OF SAID FIRST AND SECOND PINS BEING SUBSTANTIALLY PARALLEL TO SAID GIVEN AXIS, FIRST AND SECOND ROLLERS EACH HAVING A DISTAL END AND A PROXIMAL END SUBSTANTIALLY PERPENDICULAR TO THE LONGITUDINAL AXIS THEREOF, END OF SAID FIRST AND SECOND ROLLERS HAVING AN AXIAL BORE ON SAID PROXIMAL END THEREOF FOR ROTATABLY MOUNTING SAID FIRST AND SECOND ROLLERS ON SAID FIRST AND SECOND ROLLER PINS, RESPECTIVELY, RESILIENTLY SECURED DETENT MEANS INCLUDING A DETENT POSITIONED IN THE SPACE BETWEEN SAID FIRST AND SECOND ROLLERS WHEN SAID MEMBER HAS A GIVEN NEUTRAL POSITION, AT LEAST ONE OF SAID FIRST AND SECOND ROLLERS HAVING AN INDENTED SURFACE ON SAID DISTAL END THEREOF, SAID DETENT BEING POSITIONED TO COME INTO POSITIVE ENGAGEMENT WITH SAID INDENTED SURFACE ON SAID DISTAL END OF SAID ONE END ROLLER IN RESPONSE TO SAID MEMBER ROTATING THROUGH A FIRST GIVEN ANGLE IN A FIRST DIRECTION FROM ITS NEUTRAL POSITION, FIRST AND SECOND SPRING CONTACTS, SAID FIRST SPRING CONTACTS BEING POSITIONED ON SAID FRAME TO BE ACTUATED BY SAID SECOND ROLLER IN RESPONSE TO SAID MEMBER BEING ROTATED THROUGH SAID FIRST GIVEN ANGLE AND SAID SECOND SPRING CONTACTS BEING POSITIONED TO BE ACTUATED BY SAID FIRST ROLLER IN RESPONSE TO SAID MEMBER BEING ROTATED THROUGH A SECOND GIVEN ANGLE. 